棉 花 学 报       Cotton Science      2009，21(4)：307-312

Optimization of Spore Production Conditions of Antagonistic Bacteria Bacillus subtilis LZ2-70 Against Verticillium dahliae
LI Shu-na¹，WANG Shu-xiang¹，WANG Zhan-li²，LI Hong-ya¹，WANG Quan ¹，ZHU Bao-cheng^1*
(1.College of Life Science，Agricultural University of Hebei，Baoding，Hebei 071001，China；2.Department of Resources and Environment，Baoding University，Baoding，Hebei 071000，China)

Abstract：In order to improve the spore production rate and spore quantity of antagonistic strain Bacillus subtilis LZ2-70 against Verticillium dahliae , the main factors influencing spore production were investigated using shake-flask fermentation method. Through single factor experiment and orthogonal experiment, the optimal shaking flask fermentation condition of strain Bacillus subtilis LZ2-70 was determined as follows: media composed of 0.5% Maltose, 2% soybean meal, 0.05% KH₂PO⁴and 0.1% MnSO₄·H₂O, initial pH 8.0, culture time 24 h and bottle filling capacity 30 mL/250 mL, 10% inoculums volume, fermentation time 36 h, fermentation temperature 30℃, rotating speed 200 r·min^-1. Under this optimum condition, the spore quantity of strain Bacillus subtilis LZ2-70 achieves 6.6×10⁹·mL^-1 and the spore production rate achieves 98.94%.
Key words：Verticillium dahilae；antagonistic bacteria；Bacillus subtilis；fermentation；spore
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